Wafer level fan-out package and method of manufacturing the same

ABSTRACT

A method of manufacturing a wafer level fan-out package includes preparing a base substrate having a protrusion, providing a chip on a surface of the base substrate adjacent to and spaced from the protrusion, forming an encapsulation layer on the base substrate to encapsulate the chip and the protrusion, removing the base substrate to expose a surface of the chip and to form a recess corresponding to the protrusion in the encapsulation layer, and providing a passive element in the recession. The method obviates a problem of displacement of the passive element by thermal expansion of the encapsulation layer while it is being formed because the passive element is incorporated into the package after the encapsulation layer is formed.

PRIORITY STATEMENT

This application claims the benefit of priority under 35 U.S.C. § 119 toChinese Patent Application No. 201710144202.7 filed on Mar. 10, 2017,the entire contents of which are hereby incorporated by reference intheir entirety.

BACKGROUND 1. Field

The inventive concept relates to semiconductor device packagingtechnologies. More particularly, the inventive concept relates to awafer level fan-out package integrated with a passive element and to amethod of manufacturing the wafer level fan-out package.

2. Description of the Related Art

Currently, in a wafer level fan-out package integrated with a passiveelement, due to different coefficients of thermal expansion (CTE) ofelements within the wafer level fan-out package, a displacement of thepassive element is liable to occur in the wafer level fan-out package,so that a poor electrical connection is established between a circuitlayer subsequently formed on the passive element and the passiveelement. For example, when semiconductor chips and the passive elementare encapsulated with an encapsulating material such as an epoxy resin,a displacement of the passive element might occur due to thermalexpansion and contraction of the encapsulating material.

FIGS. 1A-1D are cross-sectional views illustrating a method ofmanufacturing a wafer level fan-out package according to the prior art.

Referring to FIG. 1A, a chip 120 and a passive element 130 disposedseparately from the chip 120 are formed on a base substrate 110, and anencapsulating layer 140 is formed on the base substrate 110 toencapsulate the chip 120 and the passive element 130.

Referring to FIG. 1B, the base substrate 110 is then removed from thechip 120 and the passive element 130 to expose surfaces of the chip 120and the passive element 130.

Next, referring to FIG. 1C, a circuit layer 150 is formed on the exposedsurfaces of the chip 120 and the passive element 130.

Lastly, referring to FIG. 1D, solder balls 160 are formed on the circuitlayer 150.

When forming the encapsulating layer 140 to encapsulate the chip 120 andthe passive element 130, a displacement of the passive element 130 mightoccur due to thermal expansion and contraction of materials of theencapsulating layer 140, so that a poor electrical connection isestablished between the circuit layer 150 formed on the passive elementand the passive element 130.

SUMMARY

According to the inventive concept, there is provided a method ofmanufacturing a wafer level fan-out package, including providing a basesubstrate having a surface and a protrusion protruding from the surface,setting a chip on the surface of the base substrate adjacent to andspaced laterally from the protrusion, forming an encapsulation layer onthe base substrate to encapsulate the chip and the protrusion, removingthe base substrate to expose a surface of the chip and to form a recesscorresponding to the protrusion in the encapsulation layer, andproviding a passive element in the recess.

According to another aspect of the inventive concept, there is provideda wafer level fan-out package, comprising a chip having an uppersurface, a lower surface opposite to the upper surface and end portions,an encapsulation layer covering the upper surface and the end portionsof the chip, exposing the lower surface of the chip and having anopening in a side thereof facing in the same direction as the lowersurface of the chip, a circuit layer extending along the lower surfaceof the chip and within the opening, and a passive element situatedwithin the opening and electrically conductively connected to thecircuit layer, wherein the circuit layer is interposed between thepassive element and the encapsulation layer.

According to the inventive concept, there is also provided a method ofmanufacturing a wafer level fan-out package, including placing a chipand a base substrate against each other with an active surface of thechip facing the base substrate, encapsulating the chip by forming anencapsulant on the base substrate, removing the base substrate to exposethe active surface of the chip and a surface of the encapsulant adjacentto the chip, forming a wiring structure on the active surface of thechip and on the surface of the encapsulant adjacent to the chip, andsubsequently mounting a passive electronic component on and electricallyconnecting the passive electronic component to the wiring structure.

According to the inventive concept, there is also provided a method ofmanufacturing a wafer level fan-out package, including encapsulating achip in an encapsulant with an active surface of the chip exposed and arecess defined in surface of the encapsulant adjacent to the activesurface of the chip, forming a wiring structure extending over theactive surface of the chip and that lines the recess while leaving aportion of the recess unfilled, and setting a passive electroniccomponent within the unfilled portion of the recess and mounting thepassive electronic component on and electrically connecting the passiveelectronic component to the wiring structure within the recess.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects of the inventive concept will become moreapparent and readily understood from the following detailed descriptionof examples of the inventive concept taken in conjunction with theaccompanying drawings, in which:

FIGS. 1A-1D are cross-sectional views of a wafer level fan-out packageduring the course of its manufacture and illustrating a prior artsmethod of manufacturing the package;

FIG. 2 is a schematic diagram of a cross section of an example of awafer level fan-out package according to the inventive concept;

FIGS. 3, 4, 5, 6, 7 and 8 are cross-sectional views of a wafer levelfan-out package during the course of its manufacture and togetherillustrating an example of a method of manufacturing the same accordingto the inventive concept;

FIG. 9 is an enlarged view of portion A of FIG. 2 to illustrate,schematically, a wiring structure constituting a circuit layer of awafer level fan-out package according to the inventive concept; and

FIG. 10 is a flow chart of an example of a wafer level fan-out method offabricating semiconductor packages according to the inventive concept.

DETAILED DESCRIPTION

The inventive concept will be now described more fully with reference tothe accompanying drawings, in which an example of the inventive conceptis shown. However, the inventive concept may be embodied in manydifferent forms, and should not be construed as being limited to theexample disclosed herein; rather, this example is provided so that thisdisclosure will be thorough and complete, and will fully convey theinventive concept to those ordinary skilled in the art.

Referring to FIGS. 2 and 9, a wafer level fan-out package 200 accordingto the inventive concept includes a chip 220 having an upper surface, alower surface opposite to the upper surface and end portions, and anencapsulation layer 240 covering the upper surface and the end portionsof the chip 220 and exposing the lower surface of the chip 220. Theencapsulation layer 240 defines an opening (or a recess) 241 therein onthe same side as the lower surface of the chip 220, i.e., on a sidethereof facing in the same direction as the lower surface of the chip220. A circuit layer 250 extends along the lower surface of the chip 220and lines the recess 241. The forming of the circuit layer 250 on thelower surface of the chip 220 and in the recess 241 may be performedusing a variety of wiring technology. For example, a printed circuitboard (PCB) (e.g., a flexible PCB film) may be attached, or depositionand patterning technology with respect to dielectric films and wiringpatterns in semiconductor manufacturing processes may be used, but thepresent inventive concept is not limited thereto. The circuit layer 250,as shown in FIG. 9, may have a redistribution wiring layer 270 includinga wiring patterns 271, 273 and wring vias 272 connected to the wiringpatterns 271, 273.

The wafer level fan-out package 200 also includes a passive element (or“passive electronic component”) 230 disposed in the recess 241 andelectrically conductively connected within the recess 241 to the circuitlayer 250. Passive electronic components as well understood in the artinclude resistors, capacitors, inductors and the like.

The chip 220 may be of a type well known in the art and thus, will notbe described in further detail. The chip 220 is spaced laterally fromthe recess 241 that receives the passive element 230. In the presentexample of the inventive concept, the encapsulation layer 240 comprisesan epoxy resin. However, other materials may be used the encapsulationlayer 240. In examples of the inventive concept, the recess 241 has adepth of 50 to 100 μm in the encapsulation layer 240, i.e., a dimensionof 50 to 100 μm in a vertical direction or direction perpendicular tothe upper surface of the chip 220. However, the inventive concept is notlimited thereto, and the recess 241 may have any depth appropriate foraccommodating the passive element 230.

The passive element 230 may contact the circuit layer 250. In an exampleof the inventive concept, the passive element 230 may be formed on thecircuit layer 250 through reflow soldering but, the inventive concept isnot limited to such a manner of providing the passive element 230 withinthe recess 241. In any case, the circuit layer 250 is interposed betweenthe passive element 230 and the encapsulation layer 240.

A method of manufacturing a wafer level fan-out package according to anexemplary embodiment of the present disclosure will be hereinafterdescribed in detail with reference to FIGS. 3-8.

FIGS. 3-8 illustrate an example of a method of manufacturing a waferlevel fan-out package according to the inventive concept.

Referring to FIG. 3, first, a base substrate 210 having a protrusion 211is prepared, and then a chip 220 is provided on a surface of andattached to the base substrate 210 on which the protrusion 211 isprovided, with the chip 220 disposed laterally of and spaced from theprotrusion 211. The chip 220 and the base substrate 210 may be placedagainst each other with an active surface of the chip facing a surfaceof the base substrate 210 adjacent to the protrusion 211.

In examples of the inventive concept, the distance between the uppersurface of the protrusion 211 and the upper surface of the basesubstrate 210 from which the protrusion 211 extends is 50 to 100 μm.Also, the base substrate 210 and the protrusion 211 may be unitary;however the inventive concept is not limited thereto. For example, theprotrusion 211 may be formed separately on but integral with the basesubstrate 210.

Furthermore, although only one chip 220 is shown as being mounted to thebase substrate 210, in a wafer level manufacturing method according tothe inventive concept (FIG. 10) a plurality of chips 220 can be mountedto the base substrate 210 with the base substrate 210 includingprotrusions 211 disposed adjacent to and associated with the chips 220,respectively. S10

Referring to FIG. 4, subsequently, an encapsulation layer 240 or simply“encapsulant” is formed on the base substrate 210 to encapsulate thechip 220 and the protrusion 211. In an example of the inventive concept,the encapsulation layer 240 is formed epoxy resin; however, othermaterials may be used instead. Also, the encapsulation layer 240 may beformed by any method known per se in the art for forming encapsulant inthe field.

Furthermore, the molding process shown and described here may be appliedat a wafer level across a plurality of the chips 220 attached to thebase substrate 210. That is, the encapsulation layer 240 may be formedto cover a plurality of the chips 220 and associated protrusions 211.S20 in FIG. 10.

Next, referring to FIG. 5, the base substrate 210 is removed from theencapsulation layer 240 to expose a surface of the chip 220 and to forma depression or opening 241 (referred to hereinafter as a “recess”) inthe encapsulation layer 240. Because the base substrate 210 having theprotrusion 211 is removed from the encapsulation layer 240, the recess241 is formed while exposing the surface of the chip 220. The recessthus has a shape complementary to that of the protrusion 211 in theencapsulation layer 240.

At the wafer level with respect to a plurality of chips, 250 a pluralityof such recesses are formed. S30 in FIG. 10.

Thereafter, referring to FIG. 6, a circuit layer 250 is formed on theexposed surface of the chip 220 and in the recess 241. The circuit layer250 may be a wiring structure formed by any techniques known per se inthe art. For example, as is known per se in the wafer level fan outpackaging art, per se, the circuit layer 250 may be a redistributionwiring layer 270 (See, FIG. 9) comprising inputs and outputs at oppositesurfaces of an insulating layer. Refer again to FIG. 9, for example, fora schematic illustration of an example of a wiring structure in the formof a redistribution wiring layer 270.

The circuit layer 250 may be simultaneously formed across the surfacesof a plurality chips 220 embedded in the encapsulation layer 240 and ina plurality of corresponding ones of the recesses 241. S40 in FIG. 10.

Next, referring to FIG. 7, a passive element 230 is provided in therecess 241. In an example of the inventive concept, the passive element230 is provided in the recess 241 in contact with the circuit layer 250.In an example of the inventive concept, the passive element 230 may beconnected to the circuit layer 250 by reflow soldering.

Furthermore, in examples in which a plurality of chips 220 have beenembedded in the encapsulation layer 240 and a plurality of recesses 241have been formed in the encapsulation layer 240 in association with thechips 220, passive elements 230 may be provided in the recesses 241,respectively, each electrically conductively connected to the circuitlayer 250. S50 in FIG. 10.

Lastly, referring to FIG. 8, solder balls 260 are provided on thecircuit layer 250. The solder balls 260 may be formed by any methodknown per se in the semiconductor packaging art for forming externalcontacts. The solder balls 260 provide external terminals for connectingthe package 200 to an external device, and are themselves electricallyconnected to the chip(s) 220 by the conductive layer, e.g., through aredistribution wiring layer comprising a conductive layer of wiring.

Any other steps needed to complete the wafer level fan-out package willbe readily understood and known per se to those skilled in the art andthus, will not be described in detail. For example, as described above,a plurality of chips 220 and passive elements 230 may be formed togetheras provided within the encapsulation layer 240 and recesses 241,respectively. Then a dicing process may be performed to divide or“singulate” such a structure into individual packages each of the typeshown in and described with reference to FIG. 2. S60 in FIG. 10.

According to the inventive concept as described above, a displacement ofthe passive element caused by thermal expansion of the encapsulationlayer during the forming thereof may be prevented because the passiveelement is provided in the package after the encapsulation layer isformed. Therefore, a short circuit will not occur between the passiveelement and the circuit layer.

Also, in the method of manufacturing the wafer level fan-out packageaccording to the inventive concept, manufacturing precision is greatlyimproved by forming the passive element after forming the circuit layer;also, the passive element may be re-manufactured during the forming ofthe package so as to improve the yield.

Although the inventive concept has been particularly shown and describedwith reference to examples thereof, those ordinary skilled in the artwill understand that various changes can be made in forms and details tosuch examples without departing from the spirit and scope of theinventive concept as defined in the attached claims.

What is claimed is:
 1. A method of manufacturing a wafer level fan-outpackage, comprising: placing a chip and a base substrate against eachother with an active surface of the chip facing the base substrate;encapsulating the chip by forming an encapsulant on the base substrate;removing the base substrate to expose the active surface of the chip anda surface of the encapsulant laterally adjacent to the chip; forming awiring structure on the active surface of the chip and on the surface ofthe encapsulant adjacent to the chip; and subsequently mounting apassive electronic component on and electrically connecting the passiveelectronic component to the wiring structure, wherein a recess is formedin the surface of the encapsulant laterally adjacent to the chip suchthat the recess is defined to one side of the chip in a directionparallel to said surface of the encapsulant, and the passive electroniccomponent is set within the recess such that the passive electroniccomponent is disposed to said one side of the chip in the directionparallel to said surface of the encapsulant.
 2. The method of claim 1,wherein the forming of the wiring structure comprises forming aconductive layer that lines the recess while leaving a portion of therecess unfilled, and the passive electronic component is set within saidportion of the recess where the passive electronic component is mountedon and electrically connected to the wiring structure.
 3. The method ofclaim 2, wherein the recess is formed to a depth in a range of 50 to 100μm.
 4. The method of claim 2, wherein the recess is formed by providingthe base substrate with a protrusion on which the encapsulant is formed,and the removing of the base substrate with the protrusion leaves therecess in the encapsulant, the recess having a shape complementary tothat of the protrusion.
 5. The method of claim 2, further comprisingproviding solder balls on the wiring structure after the passiveelectronic component is set in the recess, and wherein the mounting ofthe passive electronic component on and electrically connecting of thepassive electronic component to the wiring structure comprises a reflowsoldering process.
 6. A method of manufacturing a wafer level fan-outpackage, comprising: encapsulating a chip in an encapsulant with anactive surface of the chip exposed and a recess defined in a surface ofthe encapsulant laterally adjacent to the active surface of the chipsuch that the recess is located to one side of the chip in a directionparallel to said surface of the encapsulant; forming a wiring structureextending over the active surface of the chip and that lines the recesswhile leaving a portion of the recess unfilled; and setting a passiveelectronic component within said portion of the recess as disposed tosaid one side of the chip in the direction parallel to said surface ofthe encapsulant, and mounting the passive electronic component on andelectrically connecting the passive electronic component to the wiringstructure within the recess.
 7. The method of claim 6, wherein theencapsulating of the chip comprises placing the chip and a basesubstrate, having a surface and a protrusion protruding from thesurface, against each other with the active surface of the chip facingthe surface of the base substrate and the protrusion of the basesubstrate disposed laterally of the chip, and depositing encapsulatingmaterial on the base substrate to cover the chip and the protrusion. 8.The method of claim 7, wherein the encapsulating material comprises anepoxy resin.
 9. The method of claim 6, wherein the recess is formed to adepth in a range of 50 to 100 μm.
 10. The method of claim 6, furthercomprising providing solder balls on the wiring structure after thepassive electronic component is set in the recess, and wherein themounting of the passive electronic component on and electricallyconnecting of the passive electronic component to the wiring structurecomprises a reflow soldering process.
 11. The method of claim 1, whereinthe recess is formed to such a depth that a bottom of the recess isdelimited by a surface of the encapsulant at a level above that of theactive surface of the chip.
 12. The method of claim 6, wherein a bottomof the recess is delimited by a surface of the encapsulant at a levelabove that of the active surface of the chip.